There is a write-up on the history of US health insurance here: http://eh.net/encyclopedia/article/thomasson.insurance.health.us http://eh.net/encyclopedia/arti

There is a write-up on the history of US health insurance here: http://eh.net/encyclopedia/article/thomasson.insurance.health.us http://eh.net/encyclopedia/article/thomasson.insurance.healt... As I understand it, employer-sponsored health insurance is not required, but it is expected in many jobs. According to the history above, health insurance tax breaks originated with Blue Cross and Blue Shield programs in the 1930s (thought to be progressive because it helped lower-income people). Employer-sponsored health insurance became popular during WWII, when companies weren't allowed to compete on wages, but were allowed to compete on benefits. And then, for some reason (parity with BCBS?), laws were passed in the 1950s that made employer-sponsored health insurance enormously tax-advantaged.